SAN FRANCISCO — These are heady times for advocates of legalized marijuana in California — and only in small part because of the newly relaxed approach of the federal government toward medical marijuana.

State lawmakers are holding a hearing on Wednesday on the effects of a bill that would legalize, tax and regulate the drug — in what would be the first such law in the United States. Tax officials estimate the legislation could bring the struggling state about $1.4 billion a year, and though the bill’s fate in the Legislature is uncertain, Gov. Arnold Schwarzenegger, a Republican, has indicated he would be open to a “robust debate” on the issue.

California voters are also taking up legalization. Three separate initiatives are being circulated for signatures to appear on the ballot next year, all of which would permit adults to possess marijuana for personal use and allow local governments to tax it. Even opponents of legalization suggest that an initiative is likely to qualify for a statewide vote.